What is the principle of wastewater treatment by air flotation?

The working principle is that a part of the treated wastewater circulates into the dissolved air tank, and the air is supersaturated and dissolved under the condition of pressurized air, and then mixed with the raw water with flocculant at the entrance of the air flotation tank. As the pressure decreases, the supersaturated air is released, forming tiny bubbles, which quickly attach to the suspended matter and lift it to the surface of the air flotation tank.

Therefore, a sludge floating layer that is easy to remove is formed, and heavier solid substances are precipitated at the bottom of the tank and removed.

Air flotation tank has been widely used in the treatment of raw water with low turbidity, algae-rich, low temperature, high chroma and low dissolved oxygen, and also in the treatment of wastewater in oil refining, paper making, printing and dyeing industries.

Air flotation tank structure

From the appearance, it can be divided into two types: circular air flotation tank and rectangular air flotation tank;

Circular air flotation tank is called super-effect shallow air flotation, which is the most advanced air flotation equipment on the market at present. Mainly using the shallow pool theory and zero-speed principle, using the internationally advanced micro-oxidation technology and high-density ion bubble technology efficiently, the surface tension of water is changed, the dissolved oxygen in water is increased on a large scale, and a large number of short-chain organic molecules and colored groups in water are adsorbed, thus making a technological breakthrough in COD which is difficult to degrade biochemically and physically.

However, the rectangular air flotation tank is a traditional air flotation process, which only uses a large number of bubbles to float the suspended particles in the water, and the static floating effect can not be achieved during operation, and the effluent stability is generally poor.

Composition of air flotation tank

The air flotation tank is generally composed of flocculation chamber, bubble contact chamber and separation chamber. It has the functions of completing the formation and growth of flocs in water, the attachment and capture of microbubbles to flocs, and the separation of flocs from air and water. In addition to the degassing flotation tank itself, other auxiliary facilities need to be combined, such as pressure degassing flotation tank, pressure degassing tank, dissolved gas releaser, etc.